U.S. patent application number 10/671598 was filed with the patent office on 2004-04-01 for glass terminal for high-speed optical communication.
This patent application is currently assigned to SHINKO ELECTRIC INDUSTRIES CO., LTD. Invention is credited to Kojima, Tetsuya, Nakamura, Yoshihiko.
Application Number | 20040060727 10/671598 |
Document ID | / |
Family ID | 32025336 |
Filed Date | 2004-04-01 |
United States Patent
Application |
20040060727 |
Kind Code |
A1 |
Kojima, Tetsuya ; et
al. |
April 1, 2004 |
Glass terminal for high-speed optical communication
Abstract
A glass terminal for high-speed optical communication. The
terminal comprises: an eyelet member provided with an inserting
hole; an optical element mounting block fixed to the eyelet member,
the optical element mounting block having such a size to cover a
range where the inserting hole is arranged, the optical element
mounting block being provided with a coaxial hole arranged
coaxially with the inserting hole and having a diameter larger than
that of the signal lead; a signal lead being inserted into the
inserting hole and sealed with the eyelet member by means of glass
filled in the inserting hole, the signal lead being extending into
the coaxial hole; the optical element mounting block having a side
surface partially cut off so that an outer peripheral surface of
the signal lead in the coaxial hole is partially exposed.
Inventors: |
Kojima, Tetsuya;
(Nagano-shi, JP) ; Nakamura, Yoshihiko;
(Nagano-shi, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
SHINKO ELECTRIC INDUSTRIES CO.,
LTD
Nagano
JP
|
Family ID: |
32025336 |
Appl. No.: |
10/671598 |
Filed: |
September 29, 2003 |
Current U.S.
Class: |
174/152GM |
Current CPC
Class: |
G02B 6/4279 20130101;
G02B 6/4272 20130101; G02B 6/4201 20130101; H01L 2224/48091
20130101; H01L 2224/48091 20130101; H01L 2924/00014 20130101 |
Class at
Publication: |
174/152.0GM |
International
Class: |
H01B 017/26 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2002 |
JP |
2002-285451 |
Claims
1. A glass terminal for high-speed optical communication, said
terminal comprising: an eyelet member provided with an inserting
hole; an optical element mounting block fixed to said eyelet
member, said optical element mounting block having such a size to
cover a range where said inserting hole is arranged, said optical
element mounting block being provided with a coaxial hole arranged
coaxially with said inserting hole and having a diameter larger
than that of said signal lead; a signal lead being inserted into
said inserting hole and sealed with said eyelet member by means of
glass filled in said inserting hole, said signal lead being
extending into said coaxial hole; said optical element mounting
block having a side surface partially cut off so that an outer
peripheral surface of the signal lead in said coaxial hole is
partially exposed.
2. A glass terminal as set forth in claim 1, wherein said side
surface of the optical element mounting block is cut off as a
tapered surface, so that an exposed area of the outer peripheral
surface of the signal lead coaxial hole is gradually increased.
3. A glass terminal for high-speed optical communication, said
terminal comprising: a metallic eyelet member having upper and
lower surfaces and having a plurality of inserting holes extending
substantially perpendicular to said upper and lower surfaces and
spaced to each other; an optical element mounting block having a
bottom surface fixed to said upper surface of the eyelet member,
said bottom surface of the optical element mounting block having
such a size to cover a range of the upper surface of the eyelet
member where said plurality of inserting holes are arranged, said
optical element mounting block being provided with coaxial holes
arranged coaxially with said inserting holes, respectively, each of
said coaxial holes having a diameter larger than that of said
signal lead; said signal leads being sealed to said eyelet member
by means of glass filled in said inserting holes, respectively, and
extending into said respective coaxial hole; said optical element
mounting block having a side surface thereof partially cut off so
that an outer peripheral surface of each of the signal leads is
partially exposed.
4. A glass terminal as set forth in claim 3, wherein a side surface
of the optical element mounting block is cut off as a tapered
surface, so that an exposed area of the outer peripheral surface of
each of the signal leads in the respective coaxial hole is
gradually increased.
5. An optical element comprising: a glass terminal comprising: a
metallic eyelet member having upper and lower surfaces and having a
plurality of inserting holes extending substantially perpendicular
to said upper and lower surfaces and spaced to each other; an
optical element mounting block having a bottom surface fixed to
said upper surface of the eyelet member, said bottom surface of the
optical element mounting block having such a size to cover a range
of the upper surface of the eyelet member where said plurality of
inserting holes are arranged, said optical element mounting block
being provided with coaxial holes arranged coaxially with said
inserting holes, respectively, each of said coaxial holes having a
diameter larger than that of said signal lead; said signal leads
being sealed with said eyelet member by means of glass filled in
said inserting holes, respectively, and extended into said
respective coaxial hole; said optical element mounting block having
a side surface thereof partially cut off so that an outer
peripheral surface of each of the signal leads is partially
exposed; and a substrate mounted on a surface of said optical
element mounting block perpendicular to said bottom surface; and an
optical element mounted on said substrate so that said optical
element is electrically connected with said exposed portion of said
signal leads.
6. An optical element as set forth in claim 5, wherein said optical
element mounted on said substrate is electrically connected with
said exposed portion of said signal leads by means of wire-bonding.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a glass terminal and, more
specifically, to a glass terminal used for high-speed optical
communication.
[0003] 2. Description of the Related Art
[0004] A lead is sealed in an metallic eyelet member with glass and
a block-like optical element mounting section is uprightly mounted
on the eyelet member to form a glass terminal, wherein an optical
element (laser element) is mounted onto the optical element
mounting section. Thus, the glass terminal is used as an optical
semiconductor device by electrically connecting the lead to the
optical element member. FIG. 9 illustrates a conventional glass
terminal on which the optical element is mounted. In this drawing,
10 denotes an eyelet member, 12 denotes a lead which is inserted
into a through-hole provided in the eyelet member 10 and sealed
with glass, 14 denotes an optical element mounting section, and 16
denotes an optical element.
[0005] An optical semiconductor device in which the glass terminal
is used for a communication device, using high-frequency signals,
such as for optical communication. When the high-frequency signals
are used, it is necessary to take the transmission characteristic
of the signal into account for the purpose of matching it with a
characteristic impedance of a transmission path. For this purpose,
a structure of a glass terminal improved in high-frequency
characteristics has been proposed. For example, as a coaxial
structure having the lead as a core is formed in a portion in which
the lead is inserted into the eyelet and sealed with glass, it is
possible to employ a method in which the characteristic impedance
is adjusted by regulating an inner diameter of the through-hole or
an outer diameter of the lead in this coaxial structure portion or
by covering the glass surface with a covering material having a
dielectric constant different from the glass (see, for example,
Japanese Unexamined Patent Publication (Kokai) No. 6-29451).
[0006] While exclusive devices have been developed in the optical
semiconductor device for using high-frequency signals, they are
expensive. On the contrary, a glass terminal which can be produced
at a low cost is much more suitable for mass production.
[0007] In this regard, when an extremely high-frequency signal of
10 GHz is used, impedance matching becomes impossible, in the
conventional glass terminal shown in FIG. 9, even if the
characteristic impedance is regulated in the coaxial structure
portion of the lead 12, because the lead 12 is exposed as it is on
the eyelet member 10, whereby the transmission loss of the
high-frequency signal is not negligible. In the glass terminal of
the conventional type, while the characteristic impedance is
adjustable in a range from 15 to 25 .OMEGA. in a portion within the
eyelet member 10, that in a portion exposed above the eyelet member
10 is approximately 200 .OMEGA..
SUMMARY OF THE INVENTION
[0008] Accordingly, the present invention has been made to solve
these problems in the prior art.
[0009] Accordingly, an object thereof is to provide a glass
terminal capable of improving the transmission characteristic of a
high-frequency signal.
[0010] Another object of the present invention is to provide a
glass terminal, which is excellent in the transmission
characteristic of a high-frequency signal even in a lead portion
extending above the eyelet member, as well as being easily produced
in a mass-production system.
[0011] According to the present invention, there is provided a
glass terminal for high-speed optical communication, the terminal
comprising: an eyelet member provided with an inserting hole; an
optical element mounting block fixed to the eyelet member, the
optical element mounting block having such a size to cover a range
where the inserting hole is arranged, the optical element mounting
block being provided with a coaxial hole arranged coaxially with
the inserting hole and having a diameter larger than that of the
signal lead; a signal lead being inserted into the inserting hole
and sealed with the eyelet member by means of glass filled in the
inserting hole, the signal lead being extending into the coaxial
hole; and the optical element mounting block having a side surface
partially cut off so that an outer peripheral surface of the signal
lead in said coaxial hole is partially exposed.
[0012] A side surface of the optical element mounting block is cut
off as a tapered surface, so that an exposed area of the outer
peripheral surface of the signal lead coaxial hole is gradually
increased.
[0013] According to another aspect of the present invention, there
is provided a glass terminal for high-speed optical communication,
the terminal comprising: a metallic eyelet member having upper and
lower surfaces and having a plurality of inserting holes extending
substantially perpendicular to the upper and lower surfaces and
spaced from each other; an optical element mounting block having a
bottom surface fixed to the upper surface of the eyelet member, the
bottom surface of the optical element mounting block having such a
size to cover a range of the upper surface of the eyelet member
where the plurality of inserting holes are arranged, the optical
element mounting block being provided with coaxial holes arranged
coaxially with the inserting holes, respectively, each of the
coaxial holes having a diameter larger than that of the signal
lead; the signal leads being sealed with the eyelet member by means
of glass filled in the inserting holes, respectively, and extended
into the respective coaxial hole; and the optical element mounting
block having a side surface thereof partially cut off so that an
outer peripheral surface of each of the signal leads is partially
exposed.
[0014] In this case also, a side surface of the optical element
mounting block is cut off as a tapered surface, so that an exposed
area of the outer peripheral surface of each of the signal leads in
the respective coaxial hole is gradually increased.
[0015] According to a still another object of the present invention
there is provided an optical element comprises an above-mentioned
glass terminal and further comprising: a substrate mounted on a
surface of the optical element mounting block perpendicular to the
bottom surface; and an optical element mounted on the substrate so
that the optically element is electrically connected with the
exposed portion of the signal leads.
[0016] The optical element mounted on the substrate is electrically
connected with the exposed portion of the signal leads by means of
wire-bonding.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view of an optical semiconductor
device provided with a glass terminal of this invention on which an
optical element is mounted;
[0018] FIG. 2 is a front sectional view of one embodiment of the
glass terminal;
[0019] FIG. 3(A) is a plan view seen from a arrow A in FIG. 2, and
FIGS. 3(B) and 3(C) are cross-sectional views taken along line B-B
and C-C, respectively;
[0020] FIG. 4 is a sectional view illustrating the arrangement of a
signal lead, a coaxial hole and an inserting hole;
[0021] FIG. 5 is a side sectional view of the embodiment of the
glass terminal;
[0022] FIG. 6 is an illustration of the arrangement of a signal
lead and a coaxial hole;
[0023] FIG. 7 is a graph representing the high-frequency
characteristic (input signal-output signal) in the embodiment of
the glass terminal;
[0024] FIG. 8 is a graph representing the high-frequency
characteristic (input signal-input side reflection signal-output
signal) in the embodiment of the glass terminal; and
[0025] FIG. 9 is a front view of the conventional glass
terminal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The present invention will be described in more detail below
based on the preferred embodiment with reference to the attached
drawings.
[0027] FIG. 1 is a perspective view of one embodiment of the
inventive glass terminal. In this drawing, an optical element is
mounted on the glass terminal.
[0028] Reference numeral 10 denotes an eyelet member; 20 denotes a
signal lead; 21 denotes a monitor lead; and 22 denotes a ground
lead. The signal lead 20 and the monitor lead 21 are sealed with
glass in an air-tight manner, and the ground lead 22 is brazed to a
lower surface of the eyelet member 10.
[0029] Reference numeral 30 denotes an optical element mounting
section formed separately from the eyelet member 10 by a
thermal-conductive material such as copper and bonded to the upper
surface of the eyelet member 10. As illustrated, the optical
element mounting section 30 is of a block shape to facilitate the
heat dissipation from the optical element. In this regard, it is
also possible to form the optical element mounting section 30 not
only separately from the eyelet member 10 but also as one piece
with the eyelet member 10.
[0030] The characteristic structure of the glass terminal according
to this embodiment is that a bonding area, in which the optical
element mounting section 30 is bonded to the upper surface of the
eyelet member 10, is provided to include a region in which the
inserting hole for inserting the signal lead 20 is arranged, a
coaxial hole 32 for passing the signal lead 20 therethrough is
provided in the optical element mounting section 30, and the signal
lead 20 is inserted into the inserting hole of the eyelet member 10
and also into the coaxial hole 32.
[0031] FIG. 2 is a front sectional view in which the signal lead 20
is sealed in an air-tight manner with glass in the inserting hole
23 provided in the eyelet member 10 and attached to the optical
element mounting section 30 through the coaxial hole 23 provided
therein. The signal lead 20 passes through the inserting hole 23
and the coaxial hole 32 and is sealed so that an upper end thereof
is flush with the upper surface of the optical element mounting
section 30.
[0032] Reference numeral 24 denotes glass used for sealing the
signal lead 20 in the inserting hole 23 in an air-tight manner. In
this embodiment, all of the signal lead 20, the monitor lead 21 and
the ground lead 22 are made of iron-cobalt-nickel alloy, and the
glass is soft glass.
[0033] The inserting holes 23 for inserting the signal leads 20 are
provided at symmetrical positions on left and right sides of a
center line of the eyelet member 10, and the coaxial holes 32 are
provided coaxial with the respective inserting holes.
[0034] An inner diameter of the coaxial hole 32 is somewhat larger
than an outer diameter of the signal lead 20 so that a some space
remains between the outer circumference of the extension 20a of the
signal lead 20 extending upward from the inserting hole 23 of the
eyelet member 10 and the inner circumference of the coaxial hole
32.
[0035] That is, a range in which the signal lead 20 is sealed in an
air-tight manner in the eyelet member 10 is limited to the
inserting hole 23, and the glass 24 does not enter the coaxial hole
32 except for a meniscus of glass 24.
[0036] FIG. 4 illustrates the arrangement of the coaxial hole 32
and the signal lead 20, and the cross-sectional arrangement of the
signal lead 20, the inserting hole 23 and the glass 24. As the
coaxial hole 32 is formed to have a diameter smaller than that of
the inserting hole 23, an inner surface of a portion of the coaxial
hole 32 coupled to the inserting hole 23 is tapered. The glass 24
adhering to the signal lead 20 in a meniscus manner does not adhere
to the inner surface (tapered surface) of the coaxial hole 32.
[0037] FIG. 5 illustrates a side sectional view in which the signal
lead 20, the monitor lead 21 and the ground lead 22 are attached to
the eyelet member 10. Reference numeral 25 denotes an inserting
hole for inserting the monitor lead 21. The monitor lead 21 is
sealed with the glass 24 to the inserting hole 25 so that an upper
end surface thereof is flush with the upper surface of the eyelet
member 10.
[0038] The extension 20a of the signal lead 20 projected above the
eyelet member 10 is provided to pass through the coaxial hole 32 in
the optical element mounting section 30. As shown in FIG. 5, a
lateral surface of the optical element mounting section 30 in which
the coaxial hole 32 is formed is a tapered surface 34 so that an
upper portion of the coaxial hole 32 is partially exposed outside.
Thereby, part of the outer circumference of a portion of the signal
lead 20 inserted into the coaxial hole 32 is exposed from the
coaxial hole 32. The exposed lateral surface of the upper portion
of the signal lead 20 becomes a wire-bonding section.
[0039] FIG. 6 illustrates the arrangement of the coaxial hole 32
provided in the optical element mounting section 30 and the signal
lead 20 in an enlarged scale. The reason why the lateral surface of
the optical element mounting section 30 on which the coaxial hole
32 is formed in a tapered form is in that it is required that a
proximal end portion of the signal lead 20 inserted into the
coaxial hole 32 is completely encircled by the coaxial hole 32 but
the distal end portion thereof is gradually exposed outside.
[0040] In a portion of the signal lead 20 coaxial with the coaxial
hole 32, the signal lead 20 is encircled with an electro-conductor
to have a predetermined characteristic impedance, which is made
close to an impedance value in the wire-bonding section by
gradually widening the opening portion of the signal lead 20. This
is because it is necessary to expose the wire-bonding section, and
to gradually change the impedance value. Preferably, an upper end
surface of the signal lead 20 is not completely exposed outside the
optical element mounting section 30.
[0041] FIGS. 7 and 8 illustrate simulated results of the
transmission characteristic of the glass terminal for a
high-frequency signal. FIG. 7 is a frequency characteristic of the
output signal relative to the input signal, and FIG. 8 is a
frequency characteristic of the reflected signal on the input side
relative to the input signal. According to the glass terminal of
this embodiment, it is apparent that an output increases in
comparison with the conventional glass terminal (Comparative
example) as shown in FIG. 7, and the transmission characteristic is
improved as the reflection of the input signal is restricted as
shown in FIG. 8.
[0042] When the optical element is mounted to the glass terminal,
as shown in FIG. 1, a substrate 38 is bonded to a support surface
36 of formed as a surface vertical to the upper surface of the
eyelet member 10, and is connected to the respective signal leads
20 by the wire-bonding. Then, an optical element 40 mounted to the
substrate 38 is connected to a circuit formed on the substrate 30
by the wire-bonding.
[0043] A monitor element 42 is mounted in a recess formed on the
upper surface of the eyelet member 10, and connected to an upper
end surface of the monitor lead 21 and an upper end surface of the
signal lead 20 by wire-bonding.
[0044] According to the present invention, as described above, it
is possible to suitably adjust the characteristic impedance at a
position at which the signal lead is inserted into the coaxial hole
by regulating a length of the signal lead exposed from the coaxial
hole, and thus to provide the glass terminal excellent in
high-frequency characteristic. Also, by forming the lateral surface
of the optical element mounting section defining the outer surface
of the coaxial hole in a cut-off shape having a tapered surface, it
is possible to gradually increase an exposed portion of the distal
end of the signal lead inserted into the coaxial hole, and to
gradually vary the characteristic impedance value in this coaxial
structure portion in the direction of the transmission path of the
signal lead. Thus, a glass terminal improved in transmission
characteristics for a high-frequency signal is provided.
[0045] It should be understood by those skilled in the art that the
foregoing description relates to only a preferred embodiment of the
disclosed invention, and that various changes and modifications may
be made to the invention without departing the sprit and scope
thereof.
* * * * *